Imaging

Accurate diagnosis relies on obtaining information and piecing it together to obtain what is usually a ‘best guess’. In medicine, this will always be the case to a greater or lesser extent as everyone is different, and not all symptoms of the same disease present in the same way. It is surprising how often people with a clear case of arthritis can be treated for months for something completely different such as muscle strains or back pain.

MRI

Historically, to diagnose a labral tear accurately in a 1.5T scanner, you would need a doctor to inject your hip joint with a large volume dye prior to the scan (termed an arthrogram). This is because the clarity of the scans from a 1.5T scanner tends to be poor (around the hip) and the dye gives a better contrast. The arthrogram is performed under local anaesthetic, but the vast majority of patients who have had this done do not wish for another, as it can be quite uncomfortable. However, some people still consider this technique the ‘gold standard’.

Even so, MRI arthrograms have been reported to have a few problems. One is that they can ‘over-call’ labral tears (as in suggest there is one present when there is not). The other is that generally they tend to be very dark scans, which means that the doctor cannot look at the other muscles and structures around the joint which can also be implicated in your pain, it purely looks at the labrum.

With the introduction of 3 Tesla MRI scanners, the arthrogram is no longer needed as the clarity of the scans are so much better. This means a faster visit to the hospital, no injection or pain, and in fact more information as all the surrounding hip structures can be assessed as well.

Cartilage Mapping

Scanning technology has advanced to a point where we not only can see the amount of joint cartilage is present in the joint, we can also get an idea of the quality and health of it! There are a few ways of doing this, the original being termed dGEMRIC (delayed Gadolinium Enhanced MRI of Cartilage). This requires an intravenous injection of contrast (Gadolinium). The patient then walks around for 20-45 minutes and then has their scan. It is very time consuming and the intravenous injection can be an issue if you have kidney problems. Therefore, other techniques have been developed; the best one (in our view!) is T2 cartilage mapping. This does not require injections of any sort, although it does add approximately 5 minutes to your scan!

Although all of these techniques are still termed ‘experimental’ the information from the cartilage mapping helps us determine the health of your joint and the areas that may be more damaged than others. This helps the surgeon give you a more accurate prognosis about what may or may not be achieved by various surgical options.

Motion Analysis

Many different factors, and often combinations of pathologies, can cause hip pain. Our job is to unpick these so that we can help get you on the road to recovery. These, as mentioned throughout our website, rely on accurate diagnosis. Most sports injuries related to the hip joint such as labral tears are secondary to mild developmental abnormalities such as femoroacetabular impingement (FAI) and/or subtle dysplasia (shallow hip socket). These can be difficult to diagnose with plain x-rays and even MRI scans.

Currently, the best way to look at the shape of the bones is CT (computerised tomography) scans, from which you can get 3D reconstructions. This is like looking at your skeleton and is a fantastic way of assessing the way the actual joint is formed.

However, things have moved on even further. From the CT scans we can see the way your hip actually moves by sending the scans off for ‘Motion Analysis’. We work with Clinical Graphics in Holland, who specialise in breaking the scans down and rebuilding them showing us how your hip moves. This can demonstrate areas of impingement or dysplasia graphically, both helping you understand your own body, but also demonstrating where the bones should be reshaped to ensure accurate surgery and the best results.

There is a possible downside though. Like x-ray, CT does expose the patient to radiation. However, the current dose from our protocol is estimated to be the equivalent of three x-rays and so is very low. But attempting to keep this to an absolute minimum, Clinical Graphics are working on obtaining the same type of report from MRI scans. This does require specific sequences and can are harder to process. Currently, we believe the CT route to be more accurate, but are working with Clinical Graphics to help improve the MRI-based reports. It is available at the Wellington if you would prefer.